[Python-Dev] CPython optimization: storing reference counters outside of objects

Terry Reedy tjreedy at udel.edu
Tue May 24 17:44:39 CEST 2011

On 5/24/2011 8:25 AM, Sturla Molden wrote:

> Artur Siekielski is not talking about cache locality, but copy-on-write
> fork on Linux et al.
> When reference counts are updated after forking, memory pages marked
> copy-on-write are copied if they store reference counts. And then he
> quickly runs out of memory. He wants to put reference counts and
> PyObjects in different pages, so only the pages with reference counts
> get copied.
> I don't think he cares about cache locality at all, but the rest of us
> do :-)

It seems clear that separating reference counts from objects satisfies a 
specialized need and should be done in a spedial, patched version of 
CPython rather than the general distribution.

Terry Jan Reedy

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